No disease
Conditions
Interventions
Group 1: Adults under dim light: Adult participants receive caffeine (3 mg/kg body weight) once and a placebo (mannitol) once in a randomized, crossover design across two laboratory sessions. Both ses
Sponsors
Universitären Psychiatrischen Kliniken (UPK)
Eligibility
Sex/Gender
All
Age
14 Years to 40 Years
Inclusion criteria
Inclusion criteria: ? Clinically healthy ? Signed consent form of participant and, in case of adolescents, additionally of legal guardian
Exclusion criteria
Exclusion criteria: ? BMI P10 7:00 according to µMCTQ ? Subjective sleep duration on school or work days 9h according to µMCTQ ? Shift work 2 zones) <1 month prior to the first session ? Disability to understand study language ? Hormonal contraceptives ? Allergies that may interact with treatment or outcomes during our study (like intake of antihistamines) ? Pregnancy or breastfeeding ? Non-Compliance to sleep-wake times (actimetry and diary) and caffeine abstinence (diary) in 5 days prior to each experimental session ? Inability to follow study instructions
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Salivary Melatonin. To quantify circadian phase and assess the effects of caffeine and its potential synergistic interaction with light exposure, the dim light melatonin onset (DLMO) will be determined. DLMO is a precise marker to quantify the circadian rhythm and will be estimated based on salivary melatonin concentrations from multiple saliva samples taken in the evening before bed. Saliva samples (>1 mL) will be collected using Salivettes at 30-minute intervals during morning and evening hours and at 60-minute intervals throughout the day. Melatonin concentrations will be quantified using the NovoLytiX Direct Saliva Melatonin RIA (RK-DSM2-U; standard range: 0.5–50 pg/mL) or NovoLytiX Direct Saliva Melatonin ELISA (EK-DSM-U). DLMO will be calculated using the widely applied “hockey-stick” method. The area under the curve (AUC) will be calculated according to the trapezoidal method described in, starting immediately after wake-up, including an initial baseline sample obtained prior to caffeine and light exposure. The AUC will therefore reflect the reduction in melatonin in response to both light exposure and caffeine (vs placebo) treatment. | — |
Secondary
| Measure | Time frame |
|---|---|
| ? Steady-state pupil-size and light sensitivity of intrinsically photosensitive retinal ganglion cells (ipRGC), measured by pupillometry ? Salivary cortisol and caffeine levels ? Brain activity (EEG), heart rate (HR) and heart rate variability (HRV) (ECG) ? Skin temperature ( Temperature thermocouples) ? Vigilance performance (Psychomotor Vigilance Test (PVT)) ? Glucose levels (Glucose Sensor) ? Motivation and dopamine related cognitive functions (Effort task) ? Subjective Sleepiness (Karolinska Sleepiness Scale (KSS)) ? Mood (Profile of Mood States (POMS)) | — |
Countries
Switzerland
Contacts
Public ContactChristian Cajochen
Universitäre Psychiatrische Kliniken Basel
Outcome results
None listed